1. Field of the Invention
Aspects of the present invention relate to a method of and an apparatus for image enhancement. More particularly, aspects of the present invention relate to a method of and an apparatus for image enhancement which enhances luminance contrast by luminance adjustment.
2. Description of the Related Art
When a display device such as a TV, a monitor, or a mobile phone is in a brighter place where ambient illuminance is high, a human eye perceives relatively decreased luminance contrast compared to the image being actually displayed. The reduction of luminance contrast leads to a reduction of image clarity. The reduction of image clarity is called a ‘fade’ phenomenon.
For example, when the luminance contrast of an original image as shown in FIG. 1A reduces to the luminance contrast as shown in FIG. 1B due to high ambient illuminance, the fade phenomenon occurs. FIGS. 1A and 1B show mean and standard deviation (std) values.
In order to provide a clearer image, the fade phenomenon must be appropriately controlled or compensated, such as by improving the luminance contrast of the image being displayed.
A conventionally available way to improve the luminance contrast and thus reduce the fade phenomenon, is to simply expand luminance distribution. However, due to limited range of expansion of the luminance distribution, the fade phenomenon has not been effectively controlled or compensated.